This invention relates generally to communications utilizing television cable systems, and more particularly to methods and apparatus for facilitating two way oral communications utilizing television cable systems.
The availability of information services to the end user has steadily increased from two wire twisted pair telephone service through the delivery of interactive television services via a wide bandwidth port such as that offered via coaxial cable or fiber optic cable. It has become desirable to provide an economically viable physical plant for subscriber access to local telephone exchange and data service, using cable television transmission technology in combination with the channelization and signaling capabilities of a cellular-like radiotelephone technology.
Most residences and offices are connected to telephone service. Many residences and some offices are connected to a wide bandwidth cable service for the delivery of television programming. It is becoming more desirable to integrate at least these two services in a single wide bandwidth service which offers two-way communication.
Television cable systems are typically configured in a tree and branch arrangement or a hub and spoke arrangement in which many subscribers share a common branch or spoke. These networks are unlike a typical telephone network arrangement, which essentially provides an individual local loop to each subscriber. To increase the compatibility between cable distribution systems and telephone networks, it has been suggested that a segment of the spectrum carried via the cable distribution system be dedicated to a wireless telephone service. (See European Patent Application No. EP 0 421 602). As suggested, the wireless telephone service would simply displace some of the conventional cable services without integrating with the cable services for optimum spectrum utilization.
Radiotelephone services, such as cellular radiotelephone systems, provide efficient spectrum utilization by sharing the available channels among a large number of potential users by assigning radio channels and/or time slots on an as-needed basis. In addition to this user trunking of channels, the radio frequencies allocated to the channels are reused over a defined geographic area in a fashion designed to minimize interference.
The fact that radiotelephone subscribers move from place to place is a unique characteristic of this service and typically not seen in conventional land-line telephone service. A substantial amount of system control in a cellular radiotelephone system is dedicated to the accommodation of such subscriber mobility. Merely cloning a radiotelephone system in a cable distribution network, as previously suggested, is not the most efficient way of providing a two-way telephone service delivered via a cable network. Therefore, there is an unfulfilled need to provide an integrated cable television and trunked telephone service via a single two-way, wide bandwidth connection to the subscriber. This system should accomplish the service delivery in a manner which is spectrally efficient and cost effective.